Tetramethylpiperidyl-containing polysiloxane or polyamine/cyanuric cl/tetramethyl-4-piperidylamine stabilizer

ABSTRACT

A mixture for stabilizing polyolefins containing A) either (A1) at least one compound of the formula                    
     in which R 1  is for example C 1 -C 10 alkyl; R 2  is 
     C 3 -C 10 alkylene; R 3  is for example hydrogen or C 1 -C 8 alkyl; and n 1  is a number from 2 to 50; or (A2) a product obtainable by reacting a product—obtained by reaction of a polyamine of the formula                    
     in which n 2 ′, n 2 ″ and n 2 ′″ are a number from 2 to 12 with cyanuric chloride—with a compound of the formula                    
     wherein R 4  is for example hydrogen or C 1 -C 12 alkyl; and R 5  is as defined for R 3  and B) magnesium oxide, magnesium hydroxide, C) zinc oxide, zinc hydroxide or an organic salt of zinc or magnesium, or a hydrotalcite; and at least one of C 1 ) an UV absorber or C 2 ) 2 pigment.

This invention relates to a stabilizer mixture containing A) a certain sterically hindered amine compound, B) a magnesium compound or a zinc compound and C) an UV absorber and/or a pigment, the use of this stabilizer mixture for stabilizing a polyolefin against light-induced degradation and the polyolefin thus stabilized.

Several stabilizer mixtures have already been described in the prior art, for example in U.S. Pat. No. 4,929,652, U.S. Pat. No. 5,037,870, EP-A-290 388, EP-A-468 923 and EP-A-690 094.

Although numerous stabilizer systems already exist, there is still a need to improve the light stability of polyolefin furthermore.

In detail, this invention relates to a stabilizer mixture containing

A) either

(A1) at least one compound of the formula (I)

 in which R₁ is C₁-C₁₀alkyl, C₅-C₁₂cycloalkyl, C₁-C₄alkyl-substituted C₅-C₁₂cycloalkyl, phenyl or C₁-C₁₀alkyl-substituted phenyl,

R₂ is C₃-C₁₀alkylene,

R₃ is hydrogen, C₁-C₈alkyl, O, OH, C₁-C₁₈alkoxy, C₅-C₁₂cycloalkoxy, —CH₂CN, C₃-C₆alkenyl, C₇-C₉phenylalkyl, C₇-C₉phenylalkyl which is substituted on the phenyl radical by C₁-C₄alkyl; or C₁-C₈acyl and,

n₁ is a number from 2 to 50; or

(A2) a product obtainable by reacting a product, obtained by reaction of a polyamine of the formula (IIa) with cyanuric chloride, with a compound of the formula (IIb)

 in which n₂′, n₂″ and n₂′″, independently of one another, are a number from 2 to 12,

R₄ is hydrogen, C₁-C₁₂alkyl, C₅-C₁₂cycloalkyl, phenyl or C₇-C₉phenylalkyl, and

R₅ is as defined for R₃;

B) magnesium oxide, magnesium hydroxide, zinc oxide, zinc hydroxide or an organic salt of zinc or magnesium, or a hydrotalcite; and

C) either

(C1) an UV absorber or

(C2) a pigment or

(C3) an UV absorber and a pigment;

with the proviso that, when component A) is a product obtainable by reacting a product, obtained by reaction of a polyamine of the formula (IIa) with cyanuric chloride, with a compound of the formula (IIb), component B) is magnesium oxide, magnesium hydroxide or an organic salt of zinc or magnesium, or a hydrotalcite.

When component A) is a product obtainable by reacting a product, obtained by reaction of a polyamine of the formula (IIa) with cyanuric chloride, with a compound of the formula (IIb), component B) is preferably magnesium oxide, magnesium hydroxide or an organic salt of zinc or magnesium, in particular an organic salt of zinc or magnesium.

Examples of alkyl having up to 12 carbon atoms are methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, 2-ethylbutyl, n-pentyl, isopentyl, 1-methylpentyl, 1,3-dimethyl-butyl, n-hexyl, 1-methylhexyl, n-heptyl, isoheptyl, 1,1,3,3-tetramethylbutyl, 1-methylheptyl, 3-methylheptyl, n-octyl, 2-ethylhexyl, 1,1,3-trimethylhexyl, 1,1,3,3-tetramethylpentyl, nonyl, decyl, undecyl, 1-methylundecyl, dodecyl and 1,1,3,3,5,5-hexamethylhexyl. One of the preferred meanings of R₁, R₃, R₄ and R₅ is C₁-C₄alkyl. R₁, R₃ and R₅ are in particular and R₄ is in particular butyl.

Examples of alkoxy containing not more than 18 carbon atoms are methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, pentoxy, isopentoxy, hexoxy, heptoxy, octoxy, decyloxy, dodecyloxy, tetradecyloxy, hexadecyloxy and octadecyloxy. C₆-C₁₂Alkoxy, in particular heptoxy and octoxy, is one of the preferred meanings of R₃ and R₅.

Examples of C₅-C₁₂cycloalkyl are cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl and cyclododecyl. C₅-C₈cycloalkyl, in particular cyclohexyl, is preferred.

C₁-C₄Alkyl-substituted C₅-C₁₂cycloalkyl is, for example, methylcyclohexyl or dimethylcyclohexyl.

Examples of C₅-C₁₂cycloalkoxy are cyclopentoxy, cyclohexoxy, cycloheptoxy, cyclooctoxy, cyclodecyloxy and cyclododecyloxy. C₅-C₈Cycloalkoxy, in particular cyclopentoxy and cyclohexoxy, is preferred.

Phenyl which is substituted by C₁-C₁₀alkyl is, for example, methylphenyl, dimethylphenyl, trimethylphenyl, tert-butylphenyl or nonylphenyl.

C₇-C₉Phenylalkyl which is unsubstituted or substituted by C₁-C₄alkyl on the phenyl radical is, for example, benzyl, phenylethyl, methylbenzyl, dimethylbenzyl, trimethylbenzyl or tert-butylbenzyl. Benzyl is preferred.

Examples of C₃-C₆alkenyl are allyl, 2-methallyl, butenyl, pentenyl and hexenyl. Allyl is preferred. The carbon atom in position 1 is preferably saturated.

C₁-C₈acyl is preferably C₁-C₈alkanoyl, C₃-C₈alkenoyl or benzoyl. Examples are formyl, acetyl, propionyl, butyryl, pentanoyl, hexanoyl, octanoyl, benzoyl, acryloyl and crotonoyl. Acetyl is preferred.

Examples of alkylene having 3 to 10 carbon atoms are propylene, trimethylene, tetramethylene, pentamethylene, 2,2-dimethyltrimethylene, hexamethylene, trimethylhexamethylene, octamethylene and decamethylene. R₂ is preferably trimethylene.

n₁ is preferably a number from 2 to 25, in particular from 2 to 20 or 2 to 10. n₂′, n₂″ and n₂′″, independently of one another, are preferably a number from 2 to 4.

R₃ and R₅, independently of one another, are preferably hydrogen, C₁-C₄alkyl, OH, C₆-C₁₂alkoxy, C₅-C₈cycloalkoxy, allyl, benzyl or acetyl, in particular hydrogen or methyl. R₅ may be for example C₆-C₁₂akoxy or C₅-C₈cycloalkoxy.

The compounds described as component (A1) are essentially known (in some cases commercially available) and can be prepared by known processes, for example as described in U.S. Pat. No. 5,051,458, U.S. Pat. No. 5,514,738, U.S. Pat. No. 4,477,615 and Chemical Abstracts-CAS No. 136 504-96-6.

The compound described as component (A2) can be prepared analogously to known processes, for example by reaction of a polyamine of the formula (IIa) with cyanuric chloride in a molar ratio of from 1:2 to 1:4 in the presence of anhydrous lithium carbonate, sodium carbonate or potassium carbonate in an organic solvent, such as 1,2-dichloroethane, toluene, xylene, benzene, dioxane or tert-amyl alcohol, at a temperature of from −20° C. to +10° C., preferably from −10° C. to +10° C., in particular from 0° C. to +10° C., for from 2 to 8 hours, followed by reaction of the resultant product with a 2,2,6,6-tetramethyl-4-piperidylamine of the formula (IIb). The molar ratio between 2,2,6,6-tetramethyl-4-piperidylamine and polyamine of the formula (IIa) is, for example, from 4:1 to 8:1. The amount of 2,2,6,6-tetramethyl-4-piperidylamine can be added in one portion or in more than one portion at intervals of a few hours.

The polyamine of the formula (IIa):cyanuric chloride:2,2,6,6-tetramethyl-4-piperidylamine of the formula (IIb) molar ratio is preferably from 1:3:5 to 1:3:6.

The following example indicates one way of preparing the preferred compound of component (A2).

Example: 23.6 g (0.128 mol) of cyanuric chloride, 7.43 g (0.0426 mol) of N,N′-bis[3-aminopropyl]ethylenediamine and 18 g (0.13 mol) of anhydrous potassium carbonate are reacted at 5° C. for 3 hours with stirring in 250 ml of 1,2-dichloroethane. The mixture is warmed at room temperature for a further 4 hours. 27.2 g (0.128 mol) of N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine are added, and the resultant mixture is warmed at 60° C. for 2 hours. A further 18 g (0.13 mol) of anhydrous potassium carbonate are added, and the mixture is warmed at 60° C. for a further 6 hours. The solvent is removed by distillation under a slight vacuum (200 mbar) and replaced by xylene. 18.2 g (0.085 mol) of N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine and 5.2 g (0.13 mol) of ground sodium hydroxide are added, the mixture is refluxed for 2 hours and, after a further 12 hours, the water formed during the reaction is removed by azeotropic distillation. The mixture is filtered. The solution is washed with water and dried over Na₂SO₄. The solvent is evaporated, and the residue is dried at 120-130° C. in vacuo (0.1 mbar). The desired compound is obtained as a colourless resin.

In general, component (A2) can be represented for example by a compound of the formula II-1, II-2 or II-3. It can also be in the form of a mixture of these three compounds.

A preferred meaning of the formula (II-1) is

A preferred meaning of the formula (II-2) is

A preferred meaning of the formula (II-3) is

In the above formulae II-1 to II-3, n₂ is preferably a number from 1 to 20.

Component (A1) is preferably ®UVASIL 299 or ®OUVASIL 125 and component (A2) is preferably ®UVASORB HA88.

The meanings of the terminal groups which saturate the free valences in the compounds of the formulae I, II-1, II-2 and II-3 depend on the processes used for their preparation. The terminal groups can also be modified after the preparation of the compounds.

In the compounds of the formula I, the terminal group bonded to the silicon atom can be, for example, (R₁)₃Si—O—, and the terminal group bonded to the oxygen can be, for example, —Si(R₁)₃.

The compounds of the formula I can also be in the form of cyclic compounds, if n₃ is a number from 3 to 10, i.e. the free valences shown in the structural formula then form a direct bond.

In the compounds of the formulae II-1, II-2 and II-3, the terminal group bonded to. the triazine radical is, for example, Cl or a

group, and the terminal group bonded to the amino radical is, for example, hydrogen or a

group.

A preferred embodiment of this invention relates to a stabilizer mixture wherein component A) is at least one compound of the formula (I).

Preferred stabilizer mixtures are those wherein

R₁ is C₁-C₄alkyl, C₅-C₈cycloalkyl or phenyl,

R₂ is C₃-C₆alkylene, and

n₁ is a number from 2 to 25;

n₂′, n₂″ and n₂′″, independently of one another, are a number from 2 to 4, and R₄ is C₁-C₄alkyl.

Particularly preferred stabilizer mixtures are those wherein the compound of the formula (I) is

with n₁ being a number from 2 to 20; the compound of the formula (IIa) is

and the compound of the formula (IIb) is

The organic salt of zinc or magnesium defined in component B) is preferably a compound of the formula MeL₂ in which Me is zinc or magnesium and L is an anion of an organic acid or of an enol. The organic acid can, for example, be a sulfonic acid, sulfinic acid, phosphonic acid or phosphinic acid, but is preferably a carboxylic acid. The acid can be aliphatic, aromatic, araliphatic or cycloaliphatc; it can be linear or branched; it can be substituted by hydroxyl or alkoxy groups; it can be saturated or unsaturated and it preferably contains 1 to 24 carbon atoms.

Examples of carboxylic acids of this type are formic, acetic, propionic, butyrc, isobutyric, caprioic, 2-ethylcaproic, caprylic, capric, lauric, palmitic, stearic, behenic, oleic, lactic, ricinoleic, 2-ethoxypropionic, benzoic, salicylic, 4-butylbenzoic, toluic, 4-dodecylbenzoic, phenylacetic, naphthylacetic, cyclohexanecarboxylic, 4-butylcyclohexanecarboxylic or cyclohexylacetic acid. The carboxylic acid can also be a technical mixture of carboxylic acids, for example technical mixtures of fatty acids or mixtures of alkylated benzoic acids.

Examples of organic acids containing sulfur or phosphorus are methanesulfonic, ethanesulfonic, α,α-dimethylethanesulfonic, n-butanesulfonic, n-dodecanesulfonic, benzenesulfonic, toluenesulfonic, 4-nonylbenzenesulfonic, 4-dodecylbenzenesulfonic or cyclohexanesulfonic acid, dodecanesulfinic, benzenesulfinic or naphthalenesulfinic acid, butylphosphonic acid, phenylphosphonic acid, monomethyl or monoethyl phenylphosphonate, monobutyl benzylphosphonate, dibutylphosphinic acid or diphenylphosphinic acid.

If L is an enolate anion, it is preferably an anion of a β-dicarbonyl compound or of an o-acylphenol. Examples of β-dicarbonyl compounds are acetylacetone, benzoylacetone, dibenzoylmethane, ethyl acetoacetate, butyl acetoacetate, lauryl acetoacetate or α-acetylcyclohexanone. Examples of o-acylphenols are 2-acetylphenol, 2-butyroylphenol, 2-acetyl-1-naphthol, 2-benzoylphenol or salicylaldehyde. The enolate is preferably the anion of a β-dicarbonyl compound having 5 to 20 carbon atoms.

A preferred hydrotalcite is Mg_(4.5)Al₂(OH)₁₃.CO₃.3.5 H₂O (®DHT-4A, ®Kyowa Chemical Industries Co. Ltd.).

Preferred examples of component B) are magnesium acetate, laurate and stearate, zinc formate, acetate, oenanthate, laurate and stearate and zinc acetylacetonate and magnesium acetylacetonate.

In a preferred embodiment of this invention component B) as an organic salt of zinc or magnesium is preferably an acetylacetonate or an aliphatic monocarboxylate having, for example, 1 to 24 carbon atoms.

The UV absorber in component C) is preferably a 2-(2′-hydroxyphenyl)benzotriazole, a 2-hydroxybenzophenone, an ester of substituted or unsubstituted benzoic acid, an acrylate, an oxamide, a 2-(2-hydroxyphenyl)-1,3,5-triazine, a monobenzoate of resorcinol or a formamidine.

The 2-(2′-hydroxyphenyl)benzotriazole is for example 2-(2′-hydroxy-5′-methylphenyl)-benzotriazole, 2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)benzotriazole, 2-(5′-tert-butyl-2′-hydroxyphenyl)benzotriazole, 2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole, 2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)-5-chloro-benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-methylphenyl)-5-chloro-benzotriazole, 2-(3′-sec-butyl-5′-tert-butyl-2′-hydroxyphenyl)benzotriazole, 2-(2′-hydroxy-4′-hydroxyphenyl)benzotriazole, 2-(3′,5′-di-tert-amyl-2′-hydroxyphenyl)benzotriazole, 2-(3′,5′-bis-(α,α-dimethylbenzyl)-2′-hydroxyphenyl)benzotriazole, mixture of 2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)-5-chloro-benzotriazole, 2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)-5-chloro-benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl-5-chloro-benzotrazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)benzotriazole, 2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)benzotriazole, 2-(3′-dodecyl-2′-hydroxy-5′-methylphenyl)benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-isooctyloxycarbonylethyl)phenylbenzotriazole, 2,2′-methylene-bis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazole-2-ylphenol] or the transesterification product of 2-[3′-tert-butyl-5′-(2-methoxycarbonylethyl)-2′-hydroxyphenyl]-2H-benzotriazole with polyethylene glycol 300;, where R=3′-tert-butyl-4′-hydroxy-5′-2H-benzotriazol-2-ylphenyl.

2-(3′,5′-Di-tert-butyl-2′-hydroxyphenyl)-5-chloro-benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5-methylphenyl)-5-chloro-benzotriazole and 2-(3′,5′-di-tert-amyl-2′-hydroxyphenyl)benzotriazole are preferred.

The 2-hydroxybenzophenone is for example the 4-hydroxy, 4-methoxy, 4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2′,4′-trihydroxy or 2′-hydroxy-4,4′-dimethoxy derivatives. 2-Hydroxy-4-octyloxybenzophenone is preferred.

The ester of a substituted or unsubstituted benzoic acid is for example 4-tert-butyl-phenyl salicylate, phenyl salicylate, octylphenyl salicylate, dibenzoyl resorcinol, bis(4-tert-butylbenzoyl) resorcinol, benzoyl resorcinol, 2,4-di-tertbutylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl 3,5-di-tert-butyl-4-hydroxybenzoate or 2-methyl-4,6-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate.

2,4-Di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate and hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate are preferred.

The acrylate is for example ethyl α-cyano-β,β-diphenylacrylate, isooctyl α-cyano-β,β-di-phenylacrylate, methyl α-carbomethoxycinnamate, methyl α-cyano-β-methyl-p-methoxycinnamate, butyl α-cyano-β-methyl-p-methoxycinnamate, methyl α-carbomethoxy-p-methoxycinnamate or N-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline.

The oxamide is for example 4,4′-dioctyloxyoxanilide, 2,2′-diethoxyoxanilide, 2,2′-dioctyloxy-5,5′-di-tert-butoxanilide, 2,2′-didodecyloxy-5,5′-di-tert-butoxanilide, 2-ethoxy-2′-ethyloxanilide, N,N′-bis(3-dimethylaminopropyl)oxamide, 2-ethoxy-5-tert-butyl-2′-ethoxanilide or its mixture with 2-ethoxy-2′-ethyl-5,4′-di-tert-butoxanilide or mixtures of ortho- and paramethoxy-disubstituted oxanilides or mixtures of o- and p-ethoxy-disubsfituted oxanilides.

The 2-(2-hydroxyphenyl)-1,3,5-triazine is for example 2,4,6-tris(2-hydroxy-4-hydroxyphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-hydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-octyloxphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-butyloxy-propoxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine, [2-hydroxy-4-(2-hydroxy-3-octyloxy-propyloxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine, 2-[4-(dodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxy-phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxy-propoxy)phenyl]-4,6-bis(2,4-di-methylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-hexyloxy)phenyl-4,6-diphenyl-1,3,5-triazine, 2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2,4,6-tris[2-hydroxy-4-(3-butoxy-2-hydroxy-propoxy)phenyl]-1,3,5-triazine or 2-(2-hydroxyphenyl)-4-(4-methoxyphenyl)-6-phenyl-1,3,5-triazine.

2-(2-Hydroxy4-hydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and 2-(2-hydroxy-4-hexyloxy)phenyl-4,6-diphenyl-1,3,5-triazine are preferred.

The monobenzoate of resorcinol is for example the compound of the formula

The formamidine is for example the compound of the formula

The UV absorber in component C) is in particular a 2-(2′-hydroxyphenyl)benzotriazole, a 2-hydroxybenzophenone or a 2-(2-hydroxyphenyl)-1,3,5-triazine.

Component C) is preferably an UV absorber.

The pigment in component C) may be an inorganic or organic pigment.

Examples of inorganic pigments are titanium dioxide, zinc oxide, carbon black, cadmium sulfide, cadmium selenide, chromium oxide, iron oxide, lead oxide and so on.

Examples of organic pigments are azo pigments, anthraquinones, phthalocyanines, tetrachloroisoindolinones, quinacridones, isoindolines, perylenes, pyrrolopyrroles (such as Pigment Red 254) and so on.

As a pigment in component C), all pigments described in “Gächter/Müller: Plastics Additives Handbook, 3rd Edition, Hanser Publishers, Munich Vienna N.Y.”, page 647 to 659, point 11.2.1.1 to 11.2.4.2 can be used.

A particular preferred pigment is titanium dioxide.

A further preferred embodiment of this invention is a stabilizer mixture containing

A) a compound of the formula

 with n₁ being a number from 2 to 20; or

a product obtainable by reacting a product, obtained by reaction of a polyamine of the formula

 with cyanuric chloride, with a compound of the formula

B) magnesium stearate and

C) the compound

The stabilizer mixture according to the present invention is useful for stabilizing polyolefins. Examples of suitable polyolefins are shown in the following.

1. Polymers of monoolefins and diolefins, for example polypropylene, polyisobutylene, polybut-1-ene, poly-4-methylpent-1-ene, polyisoprene or polybutadiene, as well as polymers of cycloolefins, for instance of cyclopentene or norbomene, polyethylene (which optionally can be crosslinked), for example high density polyethylene (HDPE), high density and high molecular weight polyethylene (HDPE-HMW), high density and ultrahigh molecular weight polyethylene (HDPE-UHMW), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), branched low density polyethylene (BLDPE).

Polyolefins, i.e. the polymers of monoolefins exemplified in the preceding paragraph, preferably polyethylene and polypropylene, can be prepared by different, and especially by the following, methods:

a) radical polymerisation (normally under high pressure and at elevated temperature).

b) catalytic polymerisation using a catalyst that normally contains one or more than one metal of groups IVb, Vb, VIb or VII of the Periodic Table. These metals usually have one or more than one ligand, typically oxides, halides, alcoholates, esters, ethers, amines, alkyls, alkenyls and/or aryls that may be either π- or (σ-coordinated. These metal complexes may be in the free form or fixed on substrates, typically on activated magnesium chloride, titanium(III) chloride, alumina or silicon oxide. These catalysts may be soluble or insoluble in the polymerisation medium. The catalysts can be used by themselves in the polymerisation or further activators may be used, typically metal alkyls, metal hydrides, metal alkyl halides, metal alkyl oxides or metal alkyloxanes, said metals being elements of groups Ia, IIa and/or IIIa of the Periodic Table. The activators may be modified conveniently with further ester, ether, amine or silyl ether groups. These catalyst systems are usually termed Phillips, Standard Oil Indiana, Ziegler (-Natta), TNZ (DuPont), metallocene or single site catalysts (SSC).

2. Mixtures of the polymers mentioned under 1), for example mixtures of polypropylene with polyisobutylene, polypropylene with polyethylene (for example PP/HDPE, PP/LDPE) and mixtures of different types of polyethylene (for example LDPE/HDPE).

3. Copolymers of monoolefins and diolefins with each other or with other vinyl monomers, for example ethyleneipropylene copolymers, linear low density polyethylene (LLDPE) and mixtures thereof with low density polyethylene (LDPE), propylene/but-1-ene copolymers, propylene/isobutylene copolymers, ethylene/but-1-ene copolymers, ethylene/hexene copolymers, ethylene/methylpentene copolymers, ethylenemheptene copolymers, ethylene/octene copolymers, propylene/butadiene copolymers, isobutylene/isoprene copolymers, ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylate copolymers, ethylene/vinyl acetate copolymers and their copolymers with carbon monoxide or ethylene/acrylic acid copolymers and their salts (ionomers) as well as terpolymers of ethylene with propylene and a diene such as hexadiene, dicyclopentadiene or ethylidene-norbornene; and mixtures of such copolymers with one another and with polymers mentioned in 1) above, for example polypropylene/ethylene-propylene copolymers, LDPE/ethylene-vinyl acetate copolymers (EVA), LDPE/ethylene-acrylic acid copolymers (EAA), LLDPE/EVA, LLDPE/EAA and alternating or random polyalkylene/carbon monoxide copolymers and mixtures thereof with other polymers, for example polyamides.

The invention therefore furthermore relates to a composition containing a polyolefin and the novel stabilizer mixture.

The polyolefins listed above under point 1 are preferred. Polyethylene and polypropylene as well as a copolymer of polyethylene or polypropylene are particularly preferred.

The components of the novel stabilizer mixture can be added to the material to be stabilized either individually or mixed with one another. Component (A) is preferably present in an amount of 0.01 to 5%, in particular 0.05 to 1%; component (B) is preferably present in an amount of 0.005 to 1%, in particular 0.025 to 0.2%; component (C1) is preferably present in an amount of 0.01 to 1%, component (C2) is preferably present in an amount of 0.01 to 10% and component (C3) is preferably present in an amount of 0.01 to 10%. “%” is % by weight, relative to the material to be stabilized.

The ratio of the UV absorber to the pigment in component (C3) is preferably 2:1 to 1:10.

The ratio of the components (A):(B) is preferably 30:1 to 1:30, for example 20:1 to 1:20 or 20:1 to 1:10.

The ratio of the components (A):(C₁) is preferably 1:20 to 30:1, for example 1:10 to 20:1 or 1:5 to 20:1.

The ratio of the components (A):(C₂) is preferably 1:30 to 30:1, for example 1:20 to 20:1 or 1:10 to 10:1.

The ratio of the components (A):(C₃) is preferably 1:30 to 30:1, for example 1:20 to 20:1 or 1:10 to 10:1.

The novel stabilizer mixture or the individual components thereof can be incorporated into the polyolefin by known methods, for example before or during shaping or by applying the dissolved or dispersed compounds to the polyolefin, if necessary with subsequent evaporation of the solvent. The individual components of the novel stabilizer mixture can be added to the materials to be stabilized in the form of a powder, granules or a masterbatch, which contains these components in, for example, a concentration of from 2.5 to 25% by weight.

If desired, the components of the novel stabilizer mixture can be melt blended with each other before incorporation in the polyolefin.

The novel stabilizer mixture or its components can be added before or during the polymerization or before the crosslinking.

The materials stabilized in this way can be used in a wide variety of forms, for example as films, fibres, tapes, moulding compositions, profiles or as binders for paints, adhesives or putties.

The stabilized polyolefin of the invention may additionally also contain various conventional additives, for example:

1. Antioxidants

1.1. Alkylated monophenols, for example 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol, 2-(α-methylcyclohexyl)-4,6-dimethylphenol, 2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol, 2,6-di-tert-butyl-4-methoxymethylphenol, nonylphenol which are linear or branched in the side chains, for example, 2,6-di-nonyl-4-methylphenol, 2,4-dimethyl-6-(1′-methylundec-1′-yl)phenol, 2,4-dimethyl-6-(1′-methylheptadec-1′-yl)phenol, 2,4-dimethyl-6-1′-methyltridec-1′-yl)phenol and mixtures thereof.

1.2. Alkylthiomethylphenols, for example 2,4-dioctylthiomethyl-6-tert-butylphenol, 2,4-dioctylthiomethyl-6-methylphenol, 2,4-dioctylthiomethyl-6-ethylphenol, 2,6-di-dodecylthiomethyl-4-nonylphenol.

1.3. Hydroquinones and alkylated hydroquinones, for example 2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octadecyloxyphenol, 2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenyl stearate, bis-(3,5-di-tert-butyl-4-hydroxyphenyl) adipate.

1.4. Tocopherols, for example α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol and mixtures thereof (Vitamin E).

1.5. Hydroxylated thiodiphenyl ethers, for example 2,2′-thiobis(6-tert-butyl-4-methylphenol); 2,2′-thiobis(4-octylphenol), 4,4′-thiobis(6-tert-butyl-3-methylphenol), 4,4′-thiobis(6-tert-butyl-2-methylphenol), 4,4′-thiobis-(3,6-di-sec-amylphenol), 4,4′-bis-(2,6-dimethyl-4-hydroxyphenyl) disulfide.

1.6. AIlkyidenebisphenols, for example 2,2′-methylenebis(6-tert-butyl-4-methylphenol), 2,2′-methylenebis(6-tert-butyl-4-ethylphenol), 2,2′-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol], 2,2′-methylenebis(4-methyl-6-cyclohexylphenol), 2,2′-methylenebis(6-nonyl-4-methylphenol), 2,2′-methylenebis(4,6-di-tert-butylphenol), 2,2′-ethylidenebis(4,6-di-tert-butylphenol), 2,2′-ethylidenebis(6-tert-butyl-4-isobutylphenol), 2,2′-methylenebis[6-(α-methylbenzyl)-4-nonylphenol], 2,2′-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol], 4,4′-methylenebis(2,6-di-tert-butylphenol), 4,4′-methylenebis(6-tert-butyl-2-methylphenol), 1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol, 1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane, ethylene glycol bis[3,3-bis(3′-tert-butyl-4′-hydroxyphenyl)butyrate], bis(3-tert-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene, bis[2-(3′-tert-butyl-2′-hydroxy-5′-methylbenzyl)-6tert-butyl-4-methylphenyl]terephthalate, 1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane, 2,2-bis-(3,5-di-tert-butyl-4-hydroxyphenyl)propane, 2,2-bis-(5-tert-butyl-4-hydroxy2-methylphenyl)-4-n-dodecylmercaptobutane, 1,1,5,5-tetra-(5-tert-butyl-4-hydroxy2-methylphenyl)pentane.

1.7. O-, N- and S-benzyl compounds, for example 3,5,3′,5′-tetra-tert-butyl-4,4′-dihydroxydibenzyl ether, octadecyl-4-hydroxy-3,5-di-methylbenzylmercaptoacetate, tridecyl-4-hydroxy-3,5-di-tert-butylbenzylmercaptoacetate, tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine, bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate, bis(3,5-di-tert-butyl-4-hydroxybenzyl)sultide, isooctyl-3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate.

1.8. Hydromxybenzylated malonates, for example dioctadecyl-2,2-bis-(3,5-di-tert-butyl-2-hydroxybenzyl)-malonate, di-octadecyl-2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)-malonate, di-dodecylmercaptoethyl-2,2-bis-(3,5-di-tert-butyl-4-hydroxybenzyl)malonate, bis[4-(1,1,3,3-tetramethylbutyl)phenyl]-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate.

1.9. Aromatic hydroxybenzyl compounds, for example 1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, 1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol.

1.10. Triazine Compounds, for example 2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine, 1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)-hexahydro-1,3,5-triazine, 1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate.

1.11. Benzylphosphonates, for example dimethyl-2,5-di-tert-butyl-4-hydroxybenzylphosphonate, diethyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl-5-tert-butyl-4-hydroxy3-methylbenzylphosphonate, the calcium salt of the monoethyl ester of 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid.

1.12. Acylaminophenols, for example 4-hydroxylauranilide, 4-hydroxystearanilide, octyl N-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate.

1.13. Esters of β-(3.5-di-tert-butyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, n-octanol, i-octanol, octadecanol, 1,6-hexanediod, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,N′-bis(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.14. Esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid with mono-or polyhydric alcohols, e.g. with methanol, ethanol, n-octanol, i-octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,N′-bis(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, tnmethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.15. Esters of β-(3.5-dicyclohexyl-4-hydroxyphenyl)gropionic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris-(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.16. Esters of 3.5-di-tert-butyl-4-hydroxyphenyl acetic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris-(hydroxyethyl)isocyanurate, N,N′-bis(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.17. Amides of β-(3.5-di-tert-butyl-4-hydroxyphenyl)propionic acid e.g. N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine, N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamine, N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine.

1.18. Ascorbic acid (vitamin C)

1.19. Aminic antioxidants, for example N,N′-di-isopropyl-p-phenylenediamine, N,N′-di-sec-butyl-p-phenylenediamine, N,N′-bis(1,4-dimethylpentyl)-p-phenylenediamine, N,N′-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine, N,N′-bis(1-methylheptyl)-p-phenylenediamine, N,N′-dicyclohexy-p-phenylenediamine, N,N′-diphenyl-p-phenylenediamine, N,N′-bis(2-naphthyl)-p-phenylenediamine, N-isopropyl-N′-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine, N-(1-methylheptyl)-N′-phenyl-p-phenylenediamine, N-cydohexyl-N′-phenyl-p-phenylenediamine, 4-(p-toluenesulfamoyl)diphenylamine, N,N′-dimethyl-N,N′-di-sec-butyl-p-phenylenediamine, diphenylamine, N-allyidiphenylamine, 4-isopropoxydiphenylamine, N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine, N-phenyl-2-naphthylamine, octylated di-phenylamine, for example p,p′-di-tert-octyldiphenylamine, 4-n-butylaminophenol, 4-butyrylaminophenol, 4-nonanoylamino-phenol, 4-dodecanoylaminophenol, 4-octadecanoylaminophenol, bis(4-methoxyphenyl)amine, 2,6-di-tert-butyl-4-dimethylaminomethylphenol, 2,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, N,N,N′,N′-tetramethyl-4,4′-diaminodiphenylmethane, 1,2-bis[(2-methylphenyl)amino]ethane, 1,2-bis(phenylamino)propane, (o-tolyl)biguanide, Bis[4-(1′,3′-dimethylbutyl)phenyl]amine, tert-octylated N-phenyl-1-naphthylamine, a mixture of mono- and dialkylated tert-butyl/tert-octyldiphenyl-amines, a mixture of mono- and dialkylated nonyldiphenylamines, a mixture of mono- and dialkylated dodecyldiphenylamines, a mixture of mono- and dialkylated isopropyl/isohexyldiphenylamines, a mixture of mono- and dialkylated tert-butyldiphenylamines, 2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine, phenothiazine, a mixture of mono- und dialkylated tert-butyl/tert-octylphenothiazines, a mixture of mono- and dialkylated tert-octyl-phenothiazines, N-allylphenothiazin, N,N,N′,N′-tetraphenyl-1,4-diaminobut-2-ene, N,N-bis(2,2,6,6-tetramethyl-piperid-4-yl-hexamethylenediamine, bis(2,2,6,6-tetramethylpiperid-4-yl)sebacate, 2,2,6,6-tetramethylpiperidin-4-one, 2,2,6,6-tetramethylpiperdin-4-ol.

2. UV absorbers and light stabilisers

2.1 Nickel compounds, for example nickel complexes of 2,2′-thio-bis-[4-(1,1,3,3-tetramethylbutyl)phenol], such as the 1:1 or 1:2 complex, with or without additional ligands such as n-butylamine, triethanolamine or N-cyclohexyldiethanolamine, nickel dibutyldithiocarbamate, nickel salts of the monoalkyl esters, e.g. the methyl or ethyl ester, of 4-hydroxy-3,5-di-tert-butylbenzylphosphonic acid, nickel complexes of ketoximes, e.g. of 2-hydroxy-4-methylphenyl undecylketoxime, nickel complexes of 1-phenyl-4-lauroyl-5-hydroxypyrazole, with or without additional ligands.

2.2 Sterically hindered amines, for example bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)succinate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the condensate of 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, the condensate of N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-tert-octylamino-2,6-dichloro-1,3,5-triazine, tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butane-tetracarboxylate, 1,1′-(1,2-ethanediyl)bis(3,3,5,5-tetramethylpiperazinone), 4-benzoyl-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine, bis(1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonate, 3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decan-2,4-dion, bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)succinate, the condensate of N,N′-bis-(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-morpholino-2,6-dichloro-1,3,5-triazine, the condensate of 2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazine and 1,2-bis(3-aminopropylamino)ethane, the condensate of 2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazine and 1,2-bis-(3-aminopropylamino)ethane, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione, 3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidin-2,5-dione, 3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione, a mixture of 4-hexadecyloxy- and 4-stearyloxy-2,2,6,6-tetramethylpiperdine, a condensation product of N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, N-(2,2,6,6-tetramethyl-4-piperidyl)-n-dodecylsuccinimid, N-(1,2,2,6,6-pentamethyl-4-piperidyl)-n-dodecylsuccinimid, 2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4,5]decane, a reaction product of 7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro [4,5]decane und epichlorohydrin.

3. Metal deactivators, for example N,N′-diphenyloxamide, N-salicylal-N′-salicyloyl hydrazine, N,N′-bis(salicyloyl) hydrazine, N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl) hydrazine, 3-salicyloylamino-1,2,4-triazole, bis(benzylidene)oxalyl dihydrazide, oxanilide, isophthaloyl dihydrazide, sebacoyl bisphenylhydrazide, N,N′-diacetyladipoyl dihydrazide, N,N′-bis(salicyloyl)oxalyl dihydrazide, N,N′-bis(salicyloyl)thiopropionyl dihydrazide.

4. Phosphites and phosphonites, for example triphenyl phosphite, diphenyl alkyl phosphites, phenyl dialkyl phosphites, tns(nonylphenyl) phosphite, trilauryl phosphite, trioctadecyl phosphite, distearyl pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite, diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, diisodecyloxypentaerythritol diphosphite, bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite, bis(2,4,6-tris(tert-butylphenyl)pentaerythritol diphosphite, tristearyl sorbitol triphosphite, tetrakis(2,4-di-tert-butylphenyl) 4,4′-biphenylene diphosphonite, 6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g]-1,3,2-dioxaphosphocin, 6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]-1,3,2-dioxaphosphocin, bis(2,4-di-tert-butyl-6-methylphenyl)methylphosphite, bis(2,4-di-tert-butyl-6-methylphenyl)ethylphosphite.

5. Hydroxylamines, for example, N,N-dibenzylhydroxylamine, N,N-diethylhydroxylamine, N,N-dioctylhydroxylamine, N,N-dilaurylhydroxylamine, N,N-ditetradecylhydroxylamine, N,N-dihexadecylhydroxylamine, N,N-dioctadecylhydroxylamine, N-hexadecyl-N-octadecylhydroxylamine, N-heptadecyl-N-octadecylhydroxylamine, N,N-dialkylhydroxylamine derived from hydrogenated tallow amine.

6. Nitrones, for example, N-benzyl-alpha-phenyl-nitrone, N-ethyl-alpha-methyl-nitrone, N-octyl-alpha-heptyl-nitrone, N-lauryl-alpha-undecyl-nitrone, N-tetradecyl-alpha-tridecyl-nitrone, N-hexadecyl-alpha-pentadecyl-nitrone, N-octadecyl-alpha-heptadecyl-nitrone, N-hexadecyl-alpha-heptadecyl-nitrone, N-ocatadecyl-alpha-pentadecyl-nitrone, N-heptadecyl-alpha-heptadecyl-nitrone, N-octadecyl-alpha-hexadecyl-nitrone, nitrone derived from N,N-dialkylhydroxylamine derived from hydrogenated tallow amine.

7. Thiosynergists, for example, dilauryl thiodipropionate or distearyl thiodipro-pionate.

8. Peroxide scavengers, for example esters of β-thiodipropionic acid, for example the lauryl, stearyl, myristyl or tddecyl esters, mercaptobenzimidazole or the zinc salt of 2-mercaptobenzimidazole, zinc dibutyldithiocarbamate, dioctadecyl disulfide, pentaerythritol tetrakis(βdodecylmercapto)propionate.

9. Basic co-stabilisers, for example, melamine, polyvinylpyrrolidone, dicyandiamide, triallyl cyanurate, urea derivatives, hydrazine derivatives, amines, polyamides, polyurethanes, alkali metal salts and alkaline earth metal salts of higher fatty acids for example calcium stearate, zinc stearate, magnesium behenate, magnesium stearate, sodium ricinoleate and potassium palmitate, antimony pyrocatecholate or fin pyrocatecholate.

10. Nucleating agents, for example, inorganic substances such as talcum, metal oxides such as titanium dioxide or magnesium oxide, phosphates, carbonates or sulfates of, preferably, alkaline earth metals; organic compounds such as mono- or polycarboxylic acids and the salts thereof, e.g. 4-tert-butylbenzoic acid, adipic acid, diphenylacetic acid, sodium succinate or sodium benzoate; polymeric compounds such as ionic copolymers (“ionomers”).

11. Fillers and reinforcing agents, for example, calcium carbonate, silicates, glass fibres, glass bulbs, asbestos, talc, kaolin, mica, barium sulfate, metal oxides and hydroxides, carbon black, graphite, wood flour and flours or fibers of other natural products, synthetic fibers.

12. Other additives, for example, plasticisers, lubricants, emulsifiers, pigments, rheology additives, catalysts, flow-control agents, optical brighteners, flameproofing agents, antistatic agents and blowing agents.

13. Benzofuranones and indolinones, for example those disclosed in U.S. Pat. No. 4,325,863, U.S. Pat. No. 4,338,244, U.S. Pat. No. 5,175,312, U.S. Pat. No. 5,216,052, U.S. Pat. No. 5,252,643, DE-A-4316611, DE-A-4316622, DE-A-4316876, EP-A-0589839 or EP-A-0591102 or 3-[4-(2-acetoxyethoxy)phenyl]-5,7-di-tert-butyl-benzofuran-2-one, 5,7-di-tert-butyl-3-[4-(2-stearoyloxyethoxy)phenyl]benzofuran-2-one, 3,3′-bis[5,7-di-tert-butyl-3-(4-[2-hydroxyethoxy]phenyl)benzofuran-2-one], 5,7-di-tert-butyl-3-(4-ethoxyphenyl)benzofuran-2-one, 3-(4-acetoxy-3,5-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one, 3-(3,5-dimethyl-4-pivaloyloxyphenyl)-5,7-di-tert-butyl-benzofuran-2-one.

The weight ratio of the total amount of components A), B) and C) to the conventional additives can be, for example, from 1:0.1 to 1:5.

The invention furthermore relates to the use of the novel stabilizer mixture for stabilizing a polyolefin against light-induced degradation.

The examples below illustrate the invention in greater detail. All percentages and parts are by weight, unless stated otherwise.

Stabilizers used in the following Examples 1 to 3:

Light stabilizer (A-1):

The mean value of n₁ is 5.8.

Light stabilizer (A-2):

A product obtainable by reacting a product, obtained by reaction of a polyamine of the formula

with cyanuric chloride, with a compound of the formula

Light stabilizer (A-3):

The mean value of n₃ is 5.1.

UV absorber(C-1):

UV absorber(C-2):

EXAMPLE 1

Light stabilizing action in polypropylene injection-moulded plates. 100 parts of polypropylene powder (melt index: 2.4 g/10 min; measured at 230° C. and with 2.16 kg) are mixed with 0.05 part of pentaerythrityl tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 0.05 part of tris[2,4-di-tert-butylphenyl]phosphite and the stabilizer mixture indicated in Table 1 in a drum mixer, and are then granulated in an extruder at a temperature of 200° to 220° C. The resulting granulate is injection-moulded to sheets 2 mm thick in an injection-moulding machine at a temperature of 240° to 260° C.

The polypropylene sheets prepared in this manner are mounted on PMMA-plates (PMMA=polymethyl methacrylate) and are weathered in Florida (45° south, direct). At regular time intervals, the carbonyl absorption of the weathered samples is measured by means of an IR-Spectrophotometer. The exposure time until 0.5 carbonyl absorption is taken as a measure of the protective action of the stabilizer mixture.

The results are indicated in Table 1.

TABLE 1 *⁾Irradiated energy until 0.5 carbonyl Stabilizer mixture absorption in kLy 0.05 % of (A-1), 0.2 % of magnesium stearate and 312 0.05 % of (C-1) 0.05 % of (A-2), 0.2 % of magnesium stearate and 260 0.05 % of (C-1) Comparison: Stabilizer mixture according to US-A-4,929,652 234 0.05 % of (A-3), 0.2 % of magnesium stearate and 0.05 % of (C-1) *⁾ High values indicate a good stabilization.

The data shown in Table 1 clearly reveal the superiority of the stabilizer mixture according to this invention over the stabilizer mixture known from the prior art.

EXAMPLE 2

Light stabilization in polypropylene block copolymer films. 100 parts of polypropylene block copolymer powder are homogenized with 0.05 part of pentaerythrityl tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 0.10 part of tris(2,4-di-tert-butylphenyl) phosphite and with the stabilizer mixture indicated in Tables 2 and 3 in a Brabender plastograph at 200° C. for 10 minutes. The composition thus obtained is removed from the compounder as rapidly as possible and compressed in a toggle press to give a sheet with a thickness of 2-3 mm. A piece of the resultant press-moulding is cut out and pressed between two high-gloss hard aluminium foils for 6 minutes at 260 ° C. using a laboratory hydraulic press to give a film with a thickness of 0.5 mm, which is immediately cooled in a water-cooled press. Sections each measuring 60 mm×25 mm are then punched out of this 0.5 mm film and are exposed in a WEATHER-OMETER Ci 65 (black panel temperature 63±2° C., without water-spraying). These test specimens are removed from the exposure apparatus at regular intervals and tested for their carbonyl content in an IR spectrometer. The increase in the carbonyl extinction on exposure is a measure of the photooxidative degradation of the polymer and is known from experience to be associated with a deterioration in the mechanical properties.

The time (T_(0.1 measured)) needed to reach a carbonyl extinction of 0.1 is shown in Tables 2 and 3.

TABLE 2 T_(0.1) measured Stabilizer mixture in hours 0.1 % of (A-1), 0.1 % of magnesium stearate and 0.5 % 4530 of TiO₂ 0.1 % of (A-2), 0.1 % of magnesium stearate and 0.5 % 3340 of TiO₂

TABLE 3 T_(0.1) measured Stabilizer mixture in hours 0.1 % of (A-1), 0.1 % of magnesium stearate and 0.1 % 3680 of (C-2) 0.1 % of (A-2), 0.1 % of magnesium stearate and 0.1 % 3200 of (C-2)

EXAMPLE 4

Light stabilization in polypropylene block homopolymer films. 100 parts of polypropylene homopolymer powder are homogenized with 0.05 part of pentaerythrityl tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 0.05 part of tris(2,4-di-tert-butylphenyl) phosphate and with the stabilizer mixture indicated in Table 4 in a Brabender plastograph at 200° C. for 10 minutes. The composition thus obtained is removed from the compounder as rapidly as possible and compressed in a toggle press to give a sheet with a thickness of 2-3 mm. A piece of the resultant press-moulding is cut out and pressed between two high-gloss hard aluminium foils for 6 minutes at 260° C. using a laboratory hydraulic press to give a film with a thickness of 0.5 mm, which is immediately cooled in a water-cooled press. Sections each measuring 60 mm×25 mm are then punched out of this 0.5 mm film and are exposed in a WEATHER-OMETER Ci 65 (black panel temperature 63±2° C., without water-spraying). These test specimens are removed from the exposure apparatus at regular intervals and tested for their carbonyl content in an IR spectrometer. The increase in the Hi carbonyl extinction on exposure is a measure of the photooxidative degradation of the polymer and is known from experience to be associated with a deterioration in the mechanical properties.

The time (T_(0.1 measured)) needed to reach a carbonyl extinction of 0.1 is shown in Table 4.

TABLE 4 T_(0.1) measured Stabilizer mixture in hours 0.1 % of (A-1), 0.1 % of magnesium stearate and 0.5 % 3360 of TiO₂ 0.1 % of (A-2), 0.1 % of magnesium stearate and 0.5 % 2000 of TiO₂ 

What is claimed is:
 1. A stabilizer mixture for polyolefins containing A) either (A1) at least one compound of the formula (I)

 in which R₁ is C₁-C₁₀alkyl, C₅-C₁₂cycloalkyl, C₁-C₄alkyl-substituted C₅-C₁₂cycloalkyl, phenyl or C_(1-C) ₁₀alkyl-substituted phenyl, R₂ is C₃-C₁₀alkylene, R₃ is hydrogen, C₁-C₈alkyl, O, OH, C₁-C₁₈alkoxy, C₅-C₁₂cycloalkoxy, —CH₂CN, C₃-C₆alkenyl, C₇-C₉phenylalkyl, C₇-C₉phenylalkyl which is substituted on the phenyl radical by C₁-C₄alkyl; or C₁-C₈acyl and, n₁ is a number from 2 to 50; or (A2) a product obtainable by reacting a product, obtained by reaction of a polyamine of the formula (IIa) with cyanuric chloride, with a compound of the formula (IIb)

 in which n₂′, n₂″ and n₂′″, independently of one another, are a number from 2 to 12, R₄ is hydrogen, C₁-C₁₂alkyl, C₅-C₁₂cycloalkyl, phenyl or C₇-C₉phenylalkyl, and R₅ is as defined for R₃; B) magnesium oxide, magnesium hydroxide, or an organic salt of magnesium, or a hydrotalcite; and C) either (C1) an UV absorber or (C2) a pigment or (C3) an UV absorber and a pigment.
 2. A stabilizer mixture according to claim 1 wherein component B) is magnesium oxide, magnesium hydroxide, or an organic salt of magnesium.
 3. A stabilizer mixture according to claim 1 wherein component A) is at least one compound of the formula (I).
 4. A stabilizer mixture according to claim 1 wherein R₃ and R₅, independently of one another, are hydrogen, C₁-C₄alkyl, OH, C₆-C₁₂alkoxy, C₅-C₈cycloalkoxy, allyl, benzyl or acetyl.
 5. A stabilizer mixture according to claim 1 wherein R₃ and R₅, independently of one another, are hydrogen or methyl.
 6. A stabilizer mixture according to claim 1 wherein R₁ is C₁-C₄alkyl, C₅-C₈cycloalkyl or phenyl, R₂ is C₃-C₆alkylene, and n₁ is a number from 2 to 25; n₂′, n₂″ and n₂′″, independently of one another, are a number from 2 to 4, and R₄ is C₁-C₄alkyl.
 7. A stabilizer mixture according to claim 1 wherein the compound of the formula (I) is

with n₁ being a number from 2 to 20; the compound of the formula (IIa) is

and the compound of the formula (IIb) is


8. A stabilizer mixture according to claim 1 wherein the organic salt of zinc or magnesium is an acetylacetonate or an aliphatic monocarboxylate.
 9. A stabilizer mixture according to claim 1 wherein the UV absorber is a 2-(2′-hydroxyphenyl)benzotriazole, a 2-hydroxybenzophenone, an ester of substituted or unsubstituted benzoic acid, an acrylate, an oxamide, a 2-(2-hydroxyphenyl)-1,3,5-triazine, a monobenzoate of resorcinol or a formamidine.
 10. A stabilizer mixture according to claim 1 wherein the UV absorber is a 2-(2′-hydroxyphenyl)benzotriazole, a 2-hydroxybenzophenone or a 2-(2-hydroxyphenyl)-1,3,5-triazine.
 11. A stabilizer mixture according to claim 1 wherein the pigment is titanium dioxide.
 12. A stabilizer mixture according to claim 1, containing as component C) an UV absorber.
 13. A stabilizer mixture according to claim 1, containing A) a compound of the formula

 with n₁ being a number from 2 to 20; or a product obtainable by reacting a product, obtained by reaction of a polyamine of the formula

 with cyanuric chloride, with a compound of the formula

B) magnesium stearate and C) the compound 